Independently and not as an agent of the Government, the Contractor shall exert its best efforts to: Isolate homogeneous preparations of tumor associated antigens from melanoma and squamous cell carcinoma tissue in sufficient quantities to permit biological and chemical characterizations (These antigens, at various stages of purification, shall be tested for functional activity in assays of humoral and cell-mediated immunity.); Receive crude tumor extracts from the NCI Tumor Immunology Program, and perform separation procedures, and cooperate with the functional testing of these materials; and Any work with humans shall proceed in accordance with clinical protocols for which the Contractor has received written approval of the Government Project Officer.